Vitamin B3 deficiency

Traditionally caused by consuming a diet mainly composed of corn and maize.

Severe deficiency leads to pellagra, which is characterised by dermatitis, dementia, diarrhoea, and eventually death.

Lean meat, poultry, fish, and peanuts are rich in vitamin B3 (niacin); milk and eggs are rich sources of tryptophan, the precursor of niacin.

Deficiency of vitamins B2 (riboflavin) and/or B6 (pyridoxine) reduces the synthesis of niacin from tryptophan and may lead to secondary vitamin B3 deficiency.

Rare in developed countries, although there are still outbreaks in Africa, India, and China, particularly in refugees and displaced people.

In developed countries, deficiency is most commonly associated with chronic alcohol use disorder, gastrointestinal malabsorption, and certain medications (e.g., isoniazid).

As the symptoms of mild vitamin B3 deficiency are similar to those of other B vitamin (e.g., B2 and B6) deficiencies that may coexist, the cause may be difficult to define.

Treatment with nicotinamide (niacinamide) will alleviate the cutaneous and many neurological symptoms within 48 hours.

Vitamin B3, also referred to as niacin, is the generic term for nicotinic acid, its amide (nicotinamide or niacinamide), and their biologically active derivatives.[1]Gallagher ML. The nutrients and their metabolism. In: Mahan LK, Escott-Stump S, eds. Krause's food & nutrition therapy. 12th ed. St. Louis, MO: Elsevier; 2008:86-88. It is also found in the form of the pyridine nucleotide coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADPH).[1]Gallagher ML. The nutrients and their metabolism. In: Mahan LK, Escott-Stump S, eds. Krause's food & nutrition therapy. 12th ed. St. Louis, MO: Elsevier; 2008:86-88.[2]Jacob RA. Niacin. In: Bowman BA, Russell RM, eds. Present knowledge in nutrition. 8th ed. Washington, DC: ILSI Press; 2001:199-206.[3]WHO/FAO. Vitamin and mineral requirements in human nutrition. Report of a joint FAO/WHO expert consultation. Bangkok, Thailand. Rome. 2004.[4]Kirkland JB, Rawley JM. Niacin. In: Bucker RB, Suttie JW, McCormick DB, et al, eds. Handbook of vitamins. 3rd ed. Basel, Switzerland: Marcel Dekker, Inc; 2001:213-254.[5]Ghosh A, Pallavi SK, Nagpal B, et al. Role of vitamins in oral health & disease: an overview. Indian J Applied Res. 2015;5:5292-295.[6]Schellack B, Harirari P, Schellack N. B-complex vitamin deficiency and supplementation. S Afr Pharm J. 2016;83:14-19. http://www.sapj.co.za/index.php/SAPJ/article/viewFile/2234/4035 These are essential in all cells for energy production, metabolism, and DNA repair. Severe deficiency results in pellagra, which is a combined deficiency of both niacin and its precursor, tryptophan. The symptoms of deficiency are primarily dermatitis, diarrhoea, and dementia. Death results if the condition is untreated.